Piston pump incorporated by a reciprocating machine component operated by a connecting rod

ABSTRACT

A piston pump incorporated in a reciprocating component of a machine for example in a cross head or in a balancing slide of an internal combustion engine connected by a connecting rod to a crank pin of a crank shaft. The pump comprises a piston slidable in a cylindrical bore provided in the said reciprocating component and acted upon against the action of spring means directly or indirectly by the connecting rod during the oscillations which the latter performs upon the rotation of the crank shaft. The said cylindrical bore is successively connected during the displacements of the reciprocating component along guides provided in a stationary structure with suction and exhaust ports at the beginning of each suction and exhaust stroke of the pump piston.

United States Patent [72] Inventors Dante Giacosa;

Giovanni Torazza, both of Turin, Italy [21] Appl. No. 812,164

22 Filed Apr. 1,1969

[45] Patented June 1, 1971 [73] Assignee Fiat Societa Per Azion Turin, Italy [3 2] Priority Apr. 4, 1968 33 Italy [54] PISTON PUMP INCORPORATED BY A RECIPROCATING MACHINE COMPONENT OPERATED BY A CONNECTING ROD 158, 159, 163, 184/26, 32, 6 (N), 6 (Y); 230/174, 179; 123/197 (A2), 198 (C); 92/160;

Primary Examiner-William L. Freeh Assistant Examiner-John J. Vrablik Attorney-Sughrue, Rothwell, Mion, Zinn and Macpeak ABSTRACT: A piston pump incorporated in a reciprocating component of a machine for example in a cross head or in a balancing slide of an internal combustion engine connected by a connecting rod to a crank pin of a crank shaft. The pump comprises a piston slidable in a cylindrical bore provided in the said reciprocating component and acted upon against the action of spring means directly or indirectly by the connecting rod during the oscillations which the latter performs upon the rotation of the crank shaft. The said cylindrical bore is successively connected during the displacements of the reciprocating component along guides provided in a stationary structure with suction and exhaust ports at the beginning of each suc- 417/313 tion and exhaust stroke of the pump piston.

A I I 14 4 T 6 9 11 2 5 1O I 7 B 1 12 a\. R n 16' a SHEET 1 [1F 2 PATENTEU JUN 1 IS?! PISTON PUMP INCORPORATED BY A RECIPROCATING MACHINE COMPONENT OPERATED BY A CONNECTING ROD The invention provides a reciprocating piston pump adapted to be incorporated by machine components utilized for other purposes, thereby avoiding any space problem.

A further object of the invention is to provide a pump of the above mentioned type which is simple and sturdy in construction and is made up of a small number of parts.

The main characteristic feature of the pump according to the invention is that the pump comprises a spring loaded piston slidably mounted in a cylindrical bore formed in the body portion of a machine component reciprocating in a stationary structure and operated by a connecting rod, and said piston being mechanically operated against the action of said spring by the oscillations of the connecting rod so as to define inside of the said bore a compression chamber-of variable volume, the said compression chamber being alternately connected by effect of the reciprocations of the said machine component with suction and exhaust ports provided in the said stationary structure, the said machine component acting with respect to the said ports like a slide valve by connecting the said compression chamber with the suction port when the volume of the said compression chamber starts increasing and connecting the latter with the exhaust port when the said volume starts decreasing.

Further characteristic features and advantages of the invention will be understood from the appended detailed description referring to the accompanying drawings given by way of example only, wherein:

FIG. 1 is a diagrammatical axial sectional view of a piston pump according to the invention, incorporated by a machine component performing a reciprocatory movement operated by a connecting rod;

FIG. 2 is a similar view showing the pump and machine component in a further operational position, and

FIG. 3 is an axial sectional view of a pump according to a modification of FIG. 1,

FIG. 4 is a front view showing diagrammatically a plurality of suction and exhaust ports cooperating with the pump according to the modified embodiment shown in FIG. 3.

Reference numeral 1 denotes a machine component performing a reciprocatory movement and operated by a connecting rod 2, such as, for instance, a compressor piston or the cross head of an internal combustion engine, as in the embodiment shown.

The reciprocating component 1 moves over guides 10 formed in a stationary structure and carries on a pivot 3 a connecting rod 2 connected with the crank pin 40 ofa crank shaft 4.

The body portion of the reciprocating component I is provided with a shaped inner extension 5 formed with a cylindrical bore 6 in which sealingly moves a piston 7 opposed by a helical spring 8 bearing on a step in the said cylindrical bore.

The piston 7 which defines inside of the said cylindrical bore a compression or working chamber of variable volume lying at its side urged upon by the spring 8, is mechanically connected to the connecting rod 2 by means of a short rod 9 one end of which is received by a recess 10 in the piston, its other end being of semispherical shape and being received in a conical recess formed with a rounded bottom provided in a protuberance 11 on the connecting rod 2.

The compression chamber of the pump can be connected upon displacements of the reciprocating component 1 along the guides 10 through an end bore 60 with the vertically aligned and spaced suction and exhaust ports 12,13, respectively, provided in one of the said stationary guides 10, the reciprocating component 1 acting thereby like a sleeve valve capable of opening or closing the ports synchronously with the suction and delivery stroke performed by the piston 7 under the action of the angular reciprocations of the connecting rod.

Reference numeral [4 denotes the circular path of the crank-pin 40 for the connecting rod, 14 denoting the arcuate path described by the center of the semispherical end of the rod 9 bearing an the bottom of the recess 10 provided in the connecting rod.

The pump operates as follows.

When the axis of the crank-pin 4a of the shaft 4 is at ahead its top dead point, for instance at the point A, the center of the semispherical end of the rod 9 is at a, and the volume of the compression chamber defined by the piston 7 starts increasing. At the same time, the reciprocating component 1 has moved upwardly over half its stroke length, so that the bore 6a is about to intercept communication with the exhaust port 13, after a short period-the bore 60 being connected with the suction port 12.

While the crank-pin 4a moves over a semicircular path so that its axis passes from point A to point B, the center of the semispherical end of the rod 9 moves from'point a to point b, the volume of the compression chamber increasing while the piston 7 performs its suction stroke under the action of spring 8.

When the crank-pin 4a moves beyond the point B the volume of the compression chamber starts decreasing and its interconnection with the suction port is intercepted, whereupon the connection of the compression chamber and the exhaust port 13 is promptly reestablished, the exhaust stroke ending when the axis of the crank 40 again reaches its position A. v

The timing system above described with which the exhaust port closes when the volume of the compression chamber is smallest and the suction port opens when the volume of the.

said chamber is increasing, affords the highest pump efficiency and avoids any undesirable dangerous overpressure within the pump.

Where the pump is employed for sucking and pumping liquids, such as lubricating oil in an internal combustion engine, the filling'possibilities of the pump are enhanced by orienting the axis of the bore 6 in the pump with respect to the direction of movement of the reciprocating component 1 so as to utilize the inertia forces originating from the reciprocation of the reciprocating component 1; with the arrangement shown in the figures of the drawing, during the period when the axis of the crank-pin 4a moves over the path from point A to point B, the same forces are directed so as to trap the fluid within compression chamber of the pump. A similar positive action occurs at the exhaust stroke of the piston 7, during' which the inertia forces are reversed and expel liquid from the pump.

Still when employing the device for fluids, fluctuations in pressure originating from the discontinuity of the exhaust strokes, may be leveled by connecting the pump to a hydraulic accumulator of suitable volume and elasticity.

This may be obtained as shown in FIGS. 1 and 2 by connecting in series with the exhaust port 13 a chamber 15 in the top portion of which a certain quantity of air is trapped. Thischamber is provided with an orifice 16 acting as evacuating means for the fluid circuit when the fluid is a lubricant.

Discontinuity in the exhaust may moreover be cut down to one half by providing on the same reciprocating member two pumps in push-pull connection as shown in FIG. 3, wherein 7' and 7 denote the cup-shaped pistons of the said pumps, the cylinders of the latter being so arranged that their compression chambers are each in turn connected with vertically aligned suction and exhaust ports, respectively l2, 13' and 12", 13" staggered there between as shown in FIG. 4.

In FIG. 3 the pistons 7', 7" are operated by shaped exten-- sions 17,18 of the connecting rod 2 provided with end shoes acting directly on the piston bottoms.

In further embodiments of the invention the reciprocating component 1 may be provided with a larger number of parallel or series operating pumps, the reciprocations of the reciprocating member and oscillations of the connecting rod driving the said component being-utilized for operating all the pumps.

Where the reciprocating component is as described the cross head or as a balancing slide for an internal combustion engine, incorporation of the pump by the cross head or by the slide avoids the use of a special pump and controls therefor, affording a high efficiency and a satisfactory operation at high number of revolutions.

What we claim is:

1. In a machine of the type comprising a stationary structure having formed therein at least one guide surface, a component performing a reciprocatory motion along said surface, and a connecting rod hinged by its one end to the said component and by its other end to the crank-pin of a rotatable crankshaft, at least one pump comprising a piston slidable in a cylindrical bore provided in the said component arranged with its axis lying in a plane substantially parallel to the plane of oscillation of the said connecting rod, one end of the said cylindrical bore being open and facing the said connecting rod while its other end communicates with an opening provided in the surface of the said component sliding along the said guide surface, spring means arranged in the said cylindrical bore urging the piston towards the end of the said bore facing the said connecting road and .thrust means rod interposed between the said piston and the said connecting rod for opposing the free displacements of the piston under the action of the said spring means and for displacing the said piston against the action of the said spring means during the oscillations of the connecting rod in the opposite directions upon the rotation of the said crank-shaft, an upper suction port and a lower exhaust port being provided in the said guide surface in such positions as to be connected to the said opening communicating with the said cylindrical bore when the piston moves under the action of the said spring means and respectively against the said action during the said oscillations of the connecting rod.

2. In a machine of the type comprising a stationary structure having formed therein at least one guide surface, a component performing a reciprocatory motion along said surface, and a connecting rod hinged by its one end to the said component and by its other end to the crank-pin of a rotatable crankshaft, at least one pump comprising a piston slidable in a cylindrical bore provided in the said component arranged with its axis lying in a plane substantially parallel to the plane of oscillation of the said connecting rod, one end of the said cylindrical bore being open and facing the said connecting rod while its other end communicates with an opening provided in the surface of the said component sliding along the said guide surface, spring means arranged in the said cylindrical bore urging the piston towards the end of the said bore facing the said connecting rod and a reaction rod interposed between the said piston and the said connecting rod and pivotally bearing against the latter, an upper suction port and a lower exhaust port being provided in the said guide surface in such positions as to be connected to the said opening communicating with the said cylindrical bore when the piston moves under the action of the said spring means and respectively against the said action during the oscillations of the connecting rod in the opposite directions.

3. A machine as set forth in claim 1, wherein the said thrust means have the form of a shaped extension projecting from the said connecting rod and bearing by its rounded end directly on the bottom of the pump piston.

4. A machine as set forth in claim 1, wherein the axis of the said cylindrical bore is inclined with respect to the direction of the reciprocating movements of the said machine component.

5. In a machine of the type comprising a stationary structure having formed therein a pair of opposite rectilinear guides parallel to each other, a component performing a reciprocatory motion along said surface, and a connecting rod hinged by its one end to the said component and by its other end to the crank-pin of a rotatable crank-shaft, at least one pump comprising a piston slidable in a cylindrical bore provided in the said component arranged with its axis lying in a plane substantially parallel to the plane of oscillation of the said connecting rod, one end of the said c lindrical bore being open and facin the said connecting rod w 1le its other end communicates wit an opening provided in the surface of the said component sliding along one of the said guides, spring means arranged in the said cylindrical bore urging the piston towards the end of the said bore facing the said connecting rod and thrust means rod interposed between the said piston and the said connecting rod for opposing the free displacements of the piston under the action of the said spring means and for displacing the said piston against the action of the said spring means during the oscillations of the connecting rod in the opposite directions upon the rotation of the said crank-shaft, an upper suction port and a lower exhaust port being provided in the said one of the said guides in such positions as to be connected to the said opening communicating with the said cylindrical bore when the piston moves under the action of the said spring means and respectively against the said action during the said oscillations of the connecting rod. 

1. In a machine of the type comprising a stationary structure having formed therein at least one guide surface, a component performing a reciprocatory motion along said surface, and a connecting rod hinged by its one end to the said component and by its other end to the crank-pin of a rotatable crank-shaft, at least one pump comprising a piston slidable in a cylindrical bore provided in the said component arranged with its axis lying in a plane substantially parallel to the plane of oscillation of the said connecting rod, one end of the said cylindrical bore being open and facing the said connecting rod while its other end communicates with an opening provided in the surface of the said component sliding along the said guide surface, spring means arranged in the said cylindrical bore urging the piston towards the end of the said bore facing the said connecting road and thrust means rod interposed between the said piston and the said connecting rod for opposing the free displacements of the piston under the action of the said spring means and for displacing the said piston against the action of the said spring means during the oscillations of the connecting rod in the opposite directions upon the rotation of the said crank-shaft, an upper suction port and a lower exhaust port being provided in the said guide surface in such positions as to be connected to the said opening communicating with the said cylindrical bore when the piston moves under the action of the said spring means and respectively against the said action during the said oscillations of the connecting rod.
 2. In a machine of the type comprising a stationary structure having formed therein at least one guide surface, a component performing a reciprocatory motion along said surface, and a connecting rod hinged by its one end to the said component and by its other end to the crank-pin of a rotatable crank-shaft, at least one pump comprising a piston slidable in a cylindrical bore provided in the said component arranged with its axis lying in a plane substantially parallel to the plane of oscillation of the said connecting rod, one end of the said cylindrical bore being open and facing the said connecting rod while its other end communicates with an opening provided in the surface of tHe said component sliding along the said guide surface, spring means arranged in the said cylindrical bore urging the piston towards the end of the said bore facing the said connecting rod and a reaction rod interposed between the said piston and the said connecting rod and pivotally bearing against the latter, an upper suction port and a lower exhaust port being provided in the said guide surface in such positions as to be connected to the said opening communicating with the said cylindrical bore when the piston moves under the action of the said spring means and respectively against the said action during the oscillations of the connecting rod in the opposite directions.
 3. A machine as set forth in claim 1, wherein the said thrust means have the form of a shaped extension projecting from the said connecting rod and bearing by its rounded end directly on the bottom of the pump piston.
 4. A machine as set forth in claim 1, wherein the axis of the said cylindrical bore is inclined with respect to the direction of the reciprocating movements of the said machine component.
 5. In a machine of the type comprising a stationary structure having formed therein a pair of opposite rectilinear guides parallel to each other, a component performing a reciprocatory motion along said surface, and a connecting rod hinged by its one end to the said component and by its other end to the crank-pin of a rotatable crank-shaft, at least one pump comprising a piston slidable in a cylindrical bore provided in the said component arranged with its axis lying in a plane substantially parallel to the plane of oscillation of the said connecting rod, one end of the said cylindrical bore being open and facing the said connecting rod while its other end communicates with an opening provided in the surface of the said component sliding along one of the said guides, spring means arranged in the said cylindrical bore urging the piston towards the end of the said bore facing the said connecting rod and thrust means rod interposed between the said piston and the said connecting rod for opposing the free displacements of the piston under the action of the said spring means and for displacing the said piston against the action of the said spring means during the oscillations of the connecting rod in the opposite directions upon the rotation of the said crank-shaft, an upper suction port and a lower exhaust port being provided in the said one of the said guides in such positions as to be connected to the said opening communicating with the said cylindrical bore when the piston moves under the action of the said spring means and respectively against the said action during the said oscillations of the connecting rod. 